1. Field of the Invention
The present invention generally relates to a magnetic recording medium having a magnetic layer formed on a non-magnetizable support, and especially to a friction reducing agent for the magnetic recording medium.
2. Description of the Prior Art
In any magnetic recording and reproducing system, a magnetic recording medium having a magnetic layer formed on a non-magnetizable support runs in contact with guide members for the medium and with magnetic heads at a substantial velocity. As a result the magnetic recording medium must be wear resistant and have a small coefficient of friction. To reduce the coefficient of friction, the magnetic layer contains some kinds of lubricants or is coated with a layer of lubricants on a surface thereof. However, in the prior art magnetic recording medium, the coating layer of the lubricant on the magnetic layer is apt to come off easily which causes a change of the friction coefficient as the medium is used, then it is necessary to provide a substantial amount of lubricant on the magnetic layer. When the large amount of lubricant is provided on the magnetic recording medium, the lubricant diffuses into the magnetic layer which softenes and reduces the strength of the magnetic layer. When the lubricant is provided in the magnetic recording layer, that is, the mixture of magnetic powder, binder, the lubricant and so on is coated to produce a magnetic layer, the friction coefficient is not stable either and the lubricant exudes from the magnetic layer and causes a so-called blooming. When the blooming occurs, the coming off amount of powder becomes large, which causes a clogging of magnetic heads.